First Americans

I

Introduction

First Americans, the earliest humans to arrive in the Americas. The first people to come to the Americas arrived in the Western Hemisphere during the late Pleistocene Epoch (1.6 million to 10,000 years before present). Most scholars believe that these ancient ancestors of modern Native Americans were hunter-gatherers who migrated to the Americas from northeastern Asia.

For much of the 20th century it was widely believed the first Americans were the Clovis people, known by their distinctive spearpoints and other tools found across North America. The earliest Clovis sites date to 11,500 years ago. However, recent excavations in South America show that people have lived in the Americas at least 12,500 years. A growing body of evidence—from other archaeological sites to studies of the languages and genetic heritage of Native Americans—suggests the first Americans may have arrived even earlier.

Many of the details concerning the first settlement of the Americas remain shrouded in mystery. Today the search for answers involves researchers from diverse fields, including archaeology, linguistics, skeletal anatomy, and molecular biology. The challenge for researchers is to find evidence that can help determine when the first settlers arrived, how these people made their way into the Americas, and if migrating groups traveled by different routes and in multiple waves. Some archaeologists and physical anthropologists have suggested that one or more of these migrations originated from places outside of Asia, although this view is not widely accepted.

Whoever they were and whenever they arrived, the first Americans faced extraordinary challenges. These hardy settlers encountered a vast, trackless new world, one rich in animals and plants and yet entirely without other peoples. As they entered new territories, they had to locate essential resources, such as water, food, and materials to make or repair their tools. They had to learn which of the unfamiliar animals and plants would feed or cure them and which might hurt or kill them. Their efforts ultimately proved successful. By the time European exploration of the Americas began in the late 15th century, the descendants of these ancient colonizers numbered in the millions.

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II

The Late Pleistocene

From their evolutionary origins in Africa, anatomically modern humans, Homo sapiens, steadily spread out across Earth’s landmasses (see Human Evolution). By 25,000 to 35,000 years ago humans had reached the far eastern reaches of modern Siberia in northeastern Asia—a region believed to be the most likely point of departure for any early migration to North America. Humans arrived in this remote corner of the world during the last major period of the Pleistocene Epoch, or Ice Age (see ice ages). Great glaciers covered much of the Northern Hemisphere at this time. In North America two immense ice sheets, the Laurentide in the east and the Cordilleran in the west, buried much of modern Canada and Alaska, as well as northern portions of the continental United States.

Pleistocene climates and environments were different than they are today, and so too was the Earth’s surface. Glaciers had captured a significant amount of the world’s water on land. Because that water no longer drained back to the oceans, worldwide sea levels dropped. Average sea levels were as much as 135 m (440 ft) lower than they are today.

A

Beringia

As sea levels fell, large expanses of previously submerged continental shelf became dry land, including the area beneath what is now the Bering Sea. This area formed a 1,600-km- (1,000-mi-) wide land bridge that connected the northeastern tip of Asia and the western tip of modern Alaska. Known as Beringia, this natural land bridge existed from about 25,000 to nearly 10,000 years ago. It was a flat, cold, and dry landscape, covered primarily in grassland, with occasional shrubs and small trees. People and animals could use Beringia to walk from Siberia to Alaska and back.

B

Possible Migration Routes

Migrants from northeastern Asia could have trekked to Alaska with relative ease when Beringia was above sea level. But traveling south from Alaska to what is now the continental United States posed significant challenges for any would-be colonizers. There were two possible routes south for migrating people: down the Pacific coast, or by way of an interior passage along the eastern flank of the Rocky Mountains. When the Laurentide and Cordilleran ice sheets were at their maximum extent, both routes were likely impassable. The Cordilleran reached across to the Pacific shore in the west and its eastern edge abutted the Laurentide, near the present border between British Columbia and Alberta.

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